The Hills Shire Local Government Area (LGA) covers 39 major sub-catchments and contains approximately 1,200 km of waterways. Urban development within the LGA has led to a change in hydrology and stormwater runoff patterns in a number of waterways. The waterways are in various states of repair and have previously been categorised into condition classes.

Royal HaskoningDHV were engaged to assess 16 of the poor condition waterways and identify remediation options. The project involved a desktop study, site visit, risk assessment and development of concept designs and cost estimates. The risk assessment was based on Council’s template and considered risk to life, infrastructure, property and the environment and the concept designs were developed to manage risk and improve the waterway condition. The concept designs implemented a ‘Best Practice’ combination of hard and soft engineering techniques that conform to industry recognised procedures and Australian Standards. The designs considered functionality of the waterway, site constraints, impact on the environment, impact on Aboriginal and European heritage and legal requirements.

The completed site assessments and concept designs interfaced with Council’s Waterway Works Program. Each site was ranked within the Works Program, based on the risk assessment, to assist Council in prioritising sites requiring remediation.